JPS6156071B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to automatic nailers, such as pressurized pneumatic nailers.

BACKGROUND ART A pressurized pneumatic nailer has been known as an example of an automatic nailer.

This has a driving section consisting of a main piston and a main cylinder in the housing that constitutes the main body of the nailer, and compressed air is introduced into the upper chamber of the main piston by a compressor or the like, and the main piston is suddenly moved. As a result, a nail is driven out from inside the maize using a nail driver connected to the main piston. After the nail is driven out, that is, after the main piston reaches the bottom dead center, the main piston transfers the air pressure accumulated in the blowback air chamber, which is arranged in communication with the main piston lower chamber, from the main piston lower chamber side. The driving cycle for one nail is completed by receiving the main piston and returning it to the top dead center (at this time, the upper chamber of the main piston is open to the atmosphere).

In this way, conventional pressurized pneumatic nailers drive the nail by rapidly lowering the piston using pressurized air, and also return the piston to its original position, that is, top dead center, in preparation for driving the next nail. A method for returning the piston to the original position is the blowback method (when the piston is lowered, pressure is accumulated in the blowback chamber with the air in the lower chamber that increases in pressure as the piston descends, and this accumulated air pressure moves the piston from the bottom dead center to the top dead center). method) is widely used.

By the way, recently, this type of nailing machine has been used in a wide variety of ways, such as driving nails into steel plates and other hard materials, or driving large diameter and long nails, and the output has increased. Threads with large upstrokes and strokes are now being used. Along with this, the nailing machine itself has become larger, and the capacity of, for example, the blowback air chamber that constitutes the above-mentioned blowback mechanism has also become larger. However, due to this increase in size, the capacity of the blowback chamber has increased, and if only the pressure accumulated as the piston descends, the blowback chamber cannot reach enough pressure to return the piston from bottom dead center to top dead center. This results in the disadvantage that it is no longer possible to increase the pressure inside the tank.

Therefore, the present invention has been devised in view of the above-mentioned conventional situation, and it is designed to adjust the closing timing of the head valve interposed between the main piston upper chamber and the main air chamber in order to maintain the open state. The purpose of this is to delay the process.

That is, the present invention provides a main cylinder disposed within a nailing machine main body, a main piston slidably and tightly fitted into the main cylinder, a nail driving driver integrally connected to the main piston, and the above-mentioned main cylinder. a main air chamber disposed on the outer periphery of one end of the main cylinder; a head valve that selectively conducts between the main air chamber and the main piston upper chamber or between the main piston upper chamber and the atmosphere; A small diameter hole that is arranged on the outer periphery of the other end of the main cylinder and that is drilled in the main cylinder when the main piston moves to the bottom dead center is connected to the upper chamber of the main piston through a small diameter hole that is drilled in the main cylinder. A blowback air chamber that communicates with the main piston lower chamber through a large diameter hole in the head valve, and selectively between the valve upper chamber of the head valve and the main air chamber or between the valve upper chamber and the atmosphere. The pilot valve has a pilot valve that conducts electrically, and a trigger valve that selectively conducts between the lower chamber of the pilot valve and the main air chamber or between the lower chamber and the atmosphere, and when the trigger valve is pressed. Through the operation, conduction is established between the lower valve chamber of the pilot valve and the main air chamber, thereby establishing conduction between the head valve upper chamber of the head valve and the atmosphere, and thereby the main air chamber and the main piston upper chamber are connected. In the trigger valve, the trigger valve is slidably and tightly fitted into the trigger valve cylinder, and the area of the upper surface is smaller than the area of the lower surface, and the main air chamber is always connected to the upper surface. a piston portion on which the pressurized air acts, a stem portion that selectively opens and closes between the valve piston lower chamber of the valve cylinder and the atmosphere, and between the valve piston lower chamber and the main air chamber. The piston part pushes up the stem part, and conducts between the lower chamber of the valve piston and the atmosphere, thereby moving to the bottom dead center and closing the main air chamber and the pilot valve. At the same time, by releasing the push-up operation of the stem portion, the valve piston lower chamber and the atmosphere are cut off, and the valve piston lower chamber is opened through the throttle valve. The pilot valve is gradually moved to the top dead center by the pressurized air supplied into the chamber, and the time for switching conduction between the main air chamber and the lower valve chamber of the pilot valve is delayed. The present invention is characterized in that the switching time for establishing conduction between the head valve upper chamber and the main air chamber is delayed.

Embodiments of the present invention shown in the drawings will be described below.

1 and 2 show one embodiment of the present invention.

In these figures, 1 is a housing constituting the main body of the nail gun, and a main cylinder 2 is housed inside the housing, and a main piston 3 is slidably and tightly fitted into the cylinder 2. A driver 4, which serves as a nail driving section, is connected and fixed to the main piston 3 downward in FIG. Further, an annular head valve cylinder 5 is disposed at the upper end of the main cylinder 2 in FIG. 1, and a head valve 6 is tightly fitted into the cylinder 5 so as to be vertically movable in FIG.

Further, a portion 7 of the housing 1 that forms the inner portion of the head valve cylinder 5 is recessed into a concave cross-section, and its bottom surface 8 constitutes the upper end wall of the main cylinder 2 in the drawing, and is located above the main piston 3. It forms a contact surface with the end surface 31 at the top dead center. Further, a through hole 9 is bored in the cylindrical axial portion of the portion 7 for communicating the head valve cylinder 5 with the atmosphere.

Reference numeral 10 denotes a main air chamber, which is formed on the outer periphery of one end side (upper end side in the figure) of the main cylinder 2. The main air chamber 10 serves as a pressurized air reservoir connected to compression means such as a compressor through a communication port (not shown). Reference numeral 11 denotes a blowback air chamber, which is located inside the housing 1 on the other end side of the main cylinder 2 (lower end side in the figure).
The chamber 11 has through holes 12,
13 communicates with the inside of the main cylinder 2, and as the main piston 3 moves down inside the main cylinder 2, air from the lower chamber side of the piston is forced into the chamber 11 through the through holes 12 and 13. At the same time, after the main piston 3 reaches a bottom dead center (not shown), pressure is applied to the piston lower chamber side through the through holes 12 and 13 to return the main piston 3 to the top dead center position shown in FIG. It is for the purpose of Note that the through hole 12,
One of the through holes 12 of the 13, that is, the one located at the upper side in the figure, is formed to have a finer diameter than the other through hole 13, and when the main piston 3 is located at the bottom dead center (not shown), it is located on the upper chamber side of the piston. It communicates with

14 is a pilot valve, and the first piston 15 at the upper end in the figure is connected to the main air chamber 10.
The first pilot valve cylinder 16 is slidably and tightly fitted into the first pilot valve cylinder 16 formed at the upper end in the figure, and the second piston 17 at the lower end is formed at the lower end of the main air chamber 10 in the figure. It is slidably and tightly fitted into the second pilot valve cylinder 18, and furthermore, it comes into contact with a valve seat 19 formed at the lower end of the cylinder 16 in the figure, slightly below the first piston 15 in the figure. Flange part 2 for
An auxiliary piston 21 with 0 is formed.

A communication hole 2 is provided between the first pilot valve cylinder 16 and the head valve cylinder 5.
2 is disposed, and further the cylinder 16
A communication hole 23 that is open to the atmosphere is bored in the hole. 24 is a trigger valve. This trigger valve 24 has a trigger valve cylinder 25 whose upper end in the figure opens in the main air chamber 10, and a piston portion 26 is tightly fitted into the cylinder 25 so as to be able to freely slide. A stem portion 27 is slidably fitted and protruded at the lower end of the cylinder 25 in the figure, and a compression coil is provided between the piston portion 26 and the stem portion 27 to apply an elastic force so as to separate them from each other in the axial direction. A spring 28 is placed between the springs 28 and 28 so that the spring 28
8, the stem portion 27 presses the O-ring n to isolate the piston lower chamber 30 from the atmosphere, and the piston portion 26 connects the lower chamber 34 of the pilot valve 14 to the communication hole 34a, the through hole 31, and the cylinder 25.
The main air chamber 10 and the lower chamber 30 are electrically connected to the atmosphere through the communication hole 32 through the throttle valve 33. On the other hand, when the trigger lever 29 is pulled up, the main air chamber 10 is opened as shown in FIG. The lower chamber 34 of the pilot valve 14
It is designed to conduct to.

The state shown in FIG. 1 is a non-operating state, that is, a state in which the trigger lever 29 has not yet been pulled up.

In this state, nails are loaded in advance from inside the magazine into a nose (not shown), that is, a nail driving portion disposed below the cylinder 2.

In this state, the trigger lever 29 is not pulled up, so the stem portion 27 is moved by the spring 2.
It is pushed down in the figure by the elastic force of 8. Therefore, the pressurized air in the main air chamber 10 is stored in the piston lower chamber 30 via the throttle valve 33. At this time, since the area of the lower surface 26A of the piston portion 26 is larger than the area of the upper surface 26B facing the main air chamber 10, the piston portion 26 is held at the top dead center, and the lower surface 26A of the piston portion 26 is held at the top dead center. The chamber 34 is communicated with the atmosphere through a communication hole 34a, a communication hole 31, and a communication hole 32.

At this time, the pressurized air in the main air chamber 10 is acting on the upper surface 17a of the second piston 17 of the pilot valve 14 in the drawing. Therefore, the second piston 17 of the pilot valve 14 is pushed down to the bottom dead center in the cylinder 18 as shown. At this time, pilot valve 1
The first piston 15 of No. 4 blocks the communication holes 22 and 23 within the first pilot valve cylinder 16, and the auxiliary piston 21 is removed from the first pilot valve cylinder 16. Therefore, the upper chamber 16a of the first piston 15 is opened to the atmosphere through the communication hole 23, and the lower chamber 16b of the first piston 15 is connected to the head valve upper chamber 5a through the communication hole 22, and further to the main air chamber 10. It communicates with That is, the pilot valve 14
acts to conduct the pressurized air in the main air chamber 10 to the head valve upper chamber 5a,
Therefore, the head valve 6 is pushed down within the head valve cylinder 5 to the bottom dead center. That is, the head valve 6 is connected to the O-ring d at the lower end in the figure.
is pressed into contact with the upper end 2c of the main cylinder 2, thereby blocking the main piston upper chamber 2a in the cylinder 2 and the main air chamber 10, and also
a is open to the atmosphere through a through hole 9. However,
The main piston 3 is located at the top dead center of the main cylinder 2, that is, at the upper end as shown.

Therefore, in the state shown in FIG. 1, the trigger lever 29 is pulled up as shown in FIG.
That is, the trigger lever 29 is rotated counterclockwise in the figure around the fulcrum pin 29a. This state will be explained with reference to FIG. 2. The stem portion 27 comes into contact with the active end 29b of the trigger lever 29 and is pushed upward in the figure against the spring force of the coil spring 28. By pushing up the stem portion 27,
The lower piston chamber 30 and the atmosphere are communicated with each other, and the piston portion 26 is moved downward in the drawing by pressurized air within the main air chamber 10 acting on the upper surface 26B. As the piston portion 26 moves, the lower chamber 34 of the pilot valve 14 and the main air chamber 10 are connected to the communication hole 34a and the communication hole 31.
and are communicated via the communication hole 32. At this time, the pilot valve 14 is inserted into the first piston upper chamber 16a.
Since the pressure is atmospheric pressure, the lower side surface 15a of the first piston 15 in the drawing is pushed upward in FIG. 1 by the pressurized air pressure in the main air chamber 10. In this way, the pilot valve 14 is moved upward in the figure (this state is not shown).
, the first pilot valve cylinder 1
6, communication holes 22 and 23 are electrically connected between the first piston 15 and the auxiliary piston 21. Therefore, the head valve upper chamber 5a is opened to the atmosphere through the communication hole 22, the cylinder 16, and the communication hole 23.

As a result, the head valve 6 receives pressurized air pressure within the main air chamber 10 at its lower end outer peripheral portions 6a and 6b in the figure, so that the head valve cylinder 5
The inside is pushed upward in the figure, and the O-ring d at the lower end is separated from the upper edge 2c of the main cylinder 2, and the main piston upper chamber 2a inside the main cylinder 2 is moved.
and the main air chamber 10. When the head valve 6 is pushed up to the top dead center in the head valve cylinder 5, the inner peripheral tapered surface 6c of the head valve 6 comes into close contact with the tapered seat 8a on the periphery of the bottom lower surface 8 (note that these surfaces 6c and the seat 8a
(It is preferable that an O-ring is interposed therebetween, although not shown.) The communication between the main piston upper chamber 2a and the atmosphere is cut off.

In this way, when the main piston upper chamber 2a of the main cylinder 2 is communicated with the air chamber 10, the main piston 3 receives pressurized air pressure on the upper side in the figure, and is rapidly lowered in the main cylinder 2 downward in the figure. Ru. As a result, the driver 4 also descends, violently driving down the nail in the nose (not shown).
It is used to drive nails. Note that as the main piston 3 descends, the air in the main piston lower chamber 2b in the main cylinder 2 is compressed, and the air in the main piston lower chamber 2b is compressed.
2 and 13, the air flows into the blowback air chamber 11 and is stored therein. The main piston 3 is connected to each of the through holes 12 and 13 in the main cylinder 2.
When the main piston is in the upper position in the figure, the main piston lower chamber 2b is communicated with the blowback air chamber 11 through the respective through holes 12 and 13. Also,
When the main piston 3 descends to the bottom dead center (not shown), the upper through hole 12 of the through holes 12 and 13 opens.
is located above the main piston 3, that is, the lower chamber side of the main piston 3 at the bottom dead center is connected through the large diameter through hole 13, and the upper chamber side of the main piston 3 is also connected through the fine diameter through hole 12. Each of them is electrically connected to the blowback chamber 11.

Therefore, when you remove your finger from the trigger lever 29 that has been pulled up as shown in FIG. 2, the spring 28 returns the stem portion 27 to the state shown in FIG. Isolated from the atmosphere. Then, the pressurized air conducted from the main air chamber 10 to the piston lower chamber 30 through the throttle valve 33 acts on the piston portion 26 from the lower chamber 30 side, and the piston portion 26 is changed from the state shown in FIG. Push it up to the state shown in Figure 1. but,
At this time, the piston portion 26 gradually receives pressurized air pressure in the main air chamber 10 via the throttle valve 33, so that the changeover from the state shown in FIG. 2 to the state shown in FIG. 1 is delayed.

When the switching of the piston portion 26 is delayed in this manner, the pilot valve 1
The lower chamber 34 of the main air chamber 10 is opened to the atmosphere, and the pilot valve 14 is pushed down in the figure as shown in FIG. This serves to isolate the upper chamber 2a and the main air chamber 10.

Therefore, even if the main piston 3 reaches the bottom dead center in the main cylinder 2, while the downward movement of the head valve 6 in the figure is delayed as described above, the main air channel is moved to the main piston upper chamber 2a side. Pressurized air flows into the blowback air chamber 10 from inside the blowback air chamber 10, and pressurized air flows into the blowback air chamber 11 through the through hole 12 which is open to the upper chamber side of the main piston 3 located at the bottom dead center. Become.

Then, when the head valve 6 is delayed as described above and shuts off the main piston upper chamber 2a and the main air chamber 10, the main piston 3 at the bottom dead center has a large diameter through hole 13 which allows the main piston 3 to enter the blowback air chamber 11. The main piston 3 is rapidly pushed up toward the top dead center by receiving the accumulated pressure on the lower chamber side. The head valve 6 is designed to shut off the main piston upper chamber 2a and the main air chamber 10, and at the same time open the main piston upper chamber 2a to the atmosphere.

As described above, according to the present invention, it is possible to delay the timing of the closing operation to close the gap between the main air chamber of the head valve and the upper chamber of the main piston, so that there is enough air in the blowback air chamber necessary for blowback. Pressurized air can be stored.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of an automatic nailing machine showing an embodiment of the present invention, and FIG. 2 is a sectional view of a main part of the above-mentioned nailing machine after operation. 2... Main cylinder, 2a... Main piston upper chamber, 2b... Main piston lower chamber, 3... Main piston, 4... Driver, 5a... Head valve upper chamber,
6...Head valve, 10...Main air chamber,
11... Blowback air chamber, 12, 13...
Through hole, 14... Pilot valve, 24... Trigger valve, 25... Trigger valve cylinder, 26... Piston part, lower surface... 26A, upper surface... 26B, 27... Stem part, 30... Piston lower chamber, 33... Throttle valve, 3
4...Lower chamber of the second piston 17.

Claims (1)

[Claims] 1 The main cylinder installed inside the nailer body,
A main piston that is slidably and tightly fitted into the main cylinder, a nail driving driver that is integrally connected to the main piston, a main air chamber that is disposed on the outer periphery of one end of the main cylinder, and a main air chamber that is arranged on the outer periphery of one end of the main cylinder. a head valve that selectively conducts between the chamber and the upper chamber of the main piston or between the upper chamber of the main piston and the atmosphere; a blowback air chamber that communicates with the upper chamber of the main piston through a small diameter hole drilled in the main cylinder and communicates with the lower chamber of the main piston via a large diameter hole drilled in the main cylinder when the main cylinder moves; and,
A pilot valve that selectively establishes conduction between the upper chamber of the head valve and the main air chamber or between the upper chamber of the valve and the atmosphere, and a lower chamber of the pilot valve and the main air chamber. or a trigger valve that selectively conducts between the lower chamber of the pilot valve and the atmosphere, and conducts between the lower chamber of the pilot valve and the main air chamber by pressing the trigger valve. to establish continuity between the upper chamber of the head valve and the atmosphere,
In the main air chamber and the main piston upper chamber, the trigger valve is slidably and tightly fitted into the trigger valve cylinder, and the area of the upper surface is smaller than the area of the lower surface. a piston portion on which the pressurized air in the main air chamber always acts on the upper surface; a stem portion that selectively opens and closes between the lower chamber of the valve piston of the valve cylinder and the atmosphere; A throttle valve is provided between a lower chamber of the valve piston and the main air chamber, and the piston section pushes up the stem section to establish continuity between the lower chamber of the valve piston and the atmosphere. By moving the main air chamber to the dead point and establishing continuity between the main air chamber and the lower valve chamber of the pilot valve, and releasing the push-up operation of the stem portion, a connection between the lower chamber of the valve piston and the atmosphere is established. By shutting off, the valve piston is gradually moved to the top dead center by the pressurized air supplied into the lower chamber of the valve piston through the throttle valve, and the valve piston is moved between the main air chamber and the lower valve chamber of the pilot valve. An automatic nailing machine characterized in that the switching time for electrical connection between the upper chamber of the head valve of the pilot valve and the main air chamber is delayed by delaying the switching time for electrical continuity.